Improvement in balanced cut-off valves



UNITED. STATES PATENT OrmeaO B. F. MOKINLEY, OF FALMOUTH, KENTUCKY.

IMPROVEMENT IN BALANCED CUT-OFF VALVES.

Spcciiication formingpart oi' Letters Patent No. 55,5 l S, dated June 12, 1366.

To all whom it may concern:

Be it known that I, B. F. MGKINLEY, of Falmouth, in the county of Pendleton and State ot' Kentucky, have invented a new and Improved Balanced Cut-Off Valve; and l do hereby declare that the following is a i'ull, clear, and exact description thereof, which will enable others skilled in the art to make and use the same, reference being had to the accompanying drawings, forming a part ot' this specification, in which- Figure l represents a longitudinal central section oil this invention. Fig. 2 isa transverse section ofthe same, the line Fig. 1, indicating the plane of section. Fig. 3 is an inverted plan of the cut-off' valve detached. Fig. 4 is a side elevation oi' the same. Fig. 5 is an inverted plan of themain valve detached. Fig. 6 is a side elevation ofthe same.

Similarletters ofreferen ce indicatelike parts.

This invention relates to a rotary valve which revolves on a seat at the bottom of a cylindrical chamber, in combination with a cut-off valve iitted into the cylindrical chamber over the main valve and provided with a balancepiston in such a manner that by means of said piston both the cut-off and the main valve are relieved from the pressure oi' the steam or balanced, and by turning the cut-off valve in the direction against that in which the main valve revolves the steam can be cut off at any desired point of the stroke, or shut off entirely, without any effect on the exhaust, which goes on without interruption.

Arepresents a steam-cylinder, which is provided with steam-ports a a and an exhaustport, b, in the ordinary manner. From this cylinder rises a cylindrical valvechamber, B, which contains thevalve C. This valve is firmly secured to or cast solid with the spindle D, by means of which a revolving motion is imparted to the same, and it is ground down steam-tight on the seat which communicates through suitable openings and channels with the ports a a' b.

The valve O is provided with three segmental openings, c, which alternate with segmental cavities c, as clearly shown in Fie'. 5 of the drawings, and the cavities c communi cate with a central cavity, d. When the valve is placed on its seat and revolved the openings and cavities cc' are made to coincide successively with the ports a a', and the relative position of said openings and cavities is such that whenever one ofthe openings c coincides with the port a one of the cavities c will coincide with the port a', and vice versa, and it' steam is admitted to the chamber B it passes in alternately through the port a and then through the port a', and when the cylinder takes steam at one end exhausts at the other, as clearly shown in Fig. 1 ot' the drawings.

On the back ofthe valve C is iitted the cutottl valve E, which connects, by a tubular stem, c, with the balance-piston F. This piston and also the valve E are tted nicely into the cylindrical chamber B, andthe steam is admitted to said chamber through the aperture f between the piston F and valve E, so that the upward pressure ot' the steam on the piston will balance the downward pressure on the valve. Said valve is provided with two segmental openings, g g, and if these openings are brought in such a position that they are in line with the ports a a in the seat ot' the main valve, steam is admitted to the cylinder during the whole' stroke; but by turning the cutott' valve in a direction opposite to that in which the main valve rotates the steam can be cut oft at any desirable point of the stroke, and if the cut-oft' valve is turned far enough the steam is cut oft, without,however,interfer ing in the least with the exhaust of the main valve.

A suitable lever, G, serves to turn the cutoff valve E, and if this lever is connected to the governor an automatic cut-oftl is obtained.

The piston F is packed steam-tight by a stutting-box and gland, and the main valve is revolved by gearing attached to the spindle D, or by any suitable mechanism. It desired, the amount of opening forA the exhaust can be increased by additional ports in the seat.

This style ot' valve is susceptible of various modifications to suit the engine to which it is to be applied. For a large engine two valves are preferable, one for each end of the cylinder, since the combined area of the openings of two smaller valves will be equal to that of the openings of one much larger. V

My valve may also be used as an independ ent cut-ott,and in this form it can be made verycheaply and applied to almost any engine.

A give the exhaust-port of the valve considerably more lead than to the steam side, and it the steam is cut oft' at lou1 points of the stroke, in consequence of the much lessened stroke of the valve, the opening for steam is very small and contracted, and also the exhaust-passage is opened a great deal to soon.

These and other diiculties are overcome by my valve, whichis so constructed that the regulation of the cut-off does not affect the eX- haust, which goes on Without interruption, no matter bow fast the engine may run or how soon it may cutoff. lt Will cut off as certainly and precisely if the engine makes one .thou sand revolutions per minute as it' it make one hundred or only twenty per minute.

The steam can be cut off entirely from the engine, or it can be allowed on during any pointl of the stroke up to the full stroke by simply moving the lever Gr. The whole valve is very simple in its construction, and being perfectly balanced it works easily and almost free from friction.

l do not claim the devices the subject-matter of Ethan Rogers in his patent of October l0, 1865; but

What I claim as new, and desire to secure by Letters Patent. isy The adjustable cut-ofi' valve E and balance piston F, in combination with the revolving valve G, constructed and operating substantially as and for the purpose described.

B. F. MCKINLEY.

Witnesses:

H. N. NEWMAN, H. F. MONROE. 

